JP2748497B2 - Method for producing oxytitanium phthalocyanine crystal - Google Patents

Description

The present invention relates to a method for producing an oxytitanium phthalocyanine crystal, and more particularly to a novel method for producing an oxytitanium phthalocyanine crystal through an electrophotographic photoreceptor.

<Prior Art> It is known that oxytitanium phthalocyanine has a metastable α-form and a stable β-form depending on production conditions. It is also known that the crystal forms of these oxytitanium phthalocyanines mutually shift under the influence of mechanical strain, organic solvents and heat. For example, α-type oxytitanium phthalocyanine transfers to β-type by heating in an organic solvent such as N-methylpyrrolidone.

Further, an α-type oxytitanium phthalocyanine is converted into an aqueous suspension, an aromatic hydrocarbon solvent is added to the aqueous suspension, and the mixture is subjected to a heat treatment, whereby an α-ray showing a strong peak at a Bragg angle (2θ) of 27.3 ° in an X-ray diffraction spectrum. Type also β
JP-A-63-20365 discloses that a crystalline oxytitanium phthalocyanine which is not classified into a type can be obtained, and that such a crystalline oxytitanium phthalocyanine is useful, such as being expected to be applied to a recording material for an optical disk. It is described in.

<Problems to be Solved by the Invention> The present invention provides an industrially advantageous method for producing an oxytitanium phthalocyanine crystal form useful for applications such as electrophotographic photoreceptors by a novel method which has not been known in the past. It is intended to do so.

<Means for Solving the Problems> The gist of the present invention is to provide oxytitanium phthalocyanine in an aliphatic carboxylic acid solvent, sulfuric acid or R.SO ₃ H (wherein,
R represents an aliphatic or aromatic residue which may have a substituent. ), And heat-treated with a sulfonate represented by the formula (1) to obtain a Bragg (2θ ± 0.2)
Ii) A method for producing an oxytitanium phthalocyanine crystal characterized by obtaining a crystal having a main diffraction peak at 27.3 °.

<Operation> Hereinafter, the present invention will be described in more detail.

Oxytitanium phthalocyanine as a raw material of the method of the present invention may be α-type, β-type or any other crystal type,
An amorphous material may be used.

As the aliphatic carboxylic acid used, acetic acid, propionic acid, butyric acid, valeric acid and the like can be mentioned. Preferably, acetic acid is used, and the amount used is 10 to 100 times (weight ratio), preferably 20 to 50 times, the amount of oxytitanium phthalocyanine used as a raw material.

Further, as a sulfonated product represented by R.SO ₃ H,
Examples thereof include aliphatic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and butanesulfonic acid, and aromatic sulfonic acids represented by the following formula.

(Wherein R ¹ and R ² are a hydrogen atom; a hydroxyl group; a nitro group; an alkyl group such as a methyl group, an ethyl group, and a propyl group; an alkoxy group such as a methoxy group and an ethoxy group; a fluorine atom, a chlorine atom, and a bromine atom. A carboxyl group; a cyano group; an amino group; a dimethylamino group, and the like.)
Among them, toluenesulfonic acid is preferred. The amount used is 1.5 to 15 moles, preferably 3 to 5 moles relative to oxytitanium phthalocyanine.

In the method of the present invention, the heat treatment in the aliphatic carboxylic acid solvent is carried out sufficiently at a temperature close to the boiling point of the solvent, so that the desired crystal form of oxytitanium phthalocyanine can be obtained with certainty. 200 ° C, preferably 70-130
It is sufficient to perform the heat treatment at a temperature of 1 hour to 5 hours.

In the present invention, the “main diffraction peak” refers to a peak having the highest (highest) intensity in the X-ray diffraction spectrum. FIGS. 1 and 4 show examples of powder X-ray spectra of the oxytitanium phthalocyanine crystal obtained by the method of the present invention. For use in an electrophotographic photoreceptor, the main peak is a diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 °. Other than the peak, various fluctuations occur depending on fine conditions, but as shown in FIG. 1 and FIG. An oxytitanium phthalocyanine crystal showing a spectrum in which the intensity (comparison of peak heights) of all peaks is 50% or less with respect to the peak intensity of ゜ is preferable from the viewpoint of chargeability, sensitivity and the like.

<Examples> Next, the present invention will be described more specifically with reference to examples and application examples, but the present invention is not limited to the following examples unless the gist is exceeded.

Example 1 25 g of p-toluenesulfonic acid and 500 ml of acetic acid were added to 5.0 g of β-oxytitanium phthalocyanine, and the mixture was heated under reflux for 5 hours. After a long time, wash things with 500 ml of hot water,
Subsequently, the mixture was hot-washed in 500 ml of methanol. The X-ray diffraction spectrum (FIG. 1) of the obtained oxytitanium phthalocyanine (yield 4.2 g) was different from the spectra of α-type and β-type oxytitanium phthalocyanine (FIGS. 2 and 3), and the Bragg angle (2θ ± 0.2 Ii) The main diffraction peak was shown at 27.3 °.

Example 2 5.0 g of methanesulfonic acid and 100 ml of acetic acid were added to 5.0 g of β-oxytitanium phthalocyanine, and the mixture was refluxed for 5 hours. The residue was hot-washed with 200 ml of water and subsequently hot-washed with 200 ml of methanol. FIG. 4 shows an X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine (yield: 3.9 g).

Example 3 The same procedure as in Examples 1 and 2 was carried out except that the solvents and sulfonated compounds described in the table were used. In each case, the main peak was at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in the X-ray diffraction spectrum. The following oxytitanium phthalocyanine was obtained.

Application Example 1 0.4 g of the oxytitanium phthalocyanine crystal and 0.2 g of polyvinyl butyral produced in Example 1
Disperse it in a sand grinder together with 30 g of 4-methyl-2-pentanone, and apply this dispersion on an aluminum deposition layer deposited on a polyester film using a film applicator so that the dry film thickness becomes 0.3 g / m ^2. After drying, a charge generation layer was formed.

On this charge generation layer, 90 parts of N-methyl-3-carbazolecarbaldehyde diphenylhydrazone, a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Company, trade name Iupilon E)
-2000) 100 parts of a 17 μm-thick charge transfer layer were laminated to obtain an electrophotographic photosensitive member having a laminated photosensitive layer.

The half-life exposure (E1 / 2) was measured as the sensitivity of this photoreceptor using an electrostatic copying paper tester (Model SP-428, manufactured by Kawaguchi Electric Works). That is, the photoreceptor is negatively charged by corona discharge with an applied voltage set so that the corona current becomes 50 μA in a dark place, and is then exposed to 775 nm monochromatic light having an intensity of 0.125 μW / cm ² and the surface potential is −500 V The exposure dose (E1 / 2) required to halve the voltage to -250 V was calculated to be 0.22 μJ /
It was cm ^2.

At this time, the charged voltage (initial surface potential) of the photoconductor was 672 V, and the surface potential (residual potential) after exposure for 10 seconds was -7 V.

Application Example 2 Except that the oxytitanium phthalocyanine crystal used was replaced with the crystal produced in Example 2, the half-exposure dose (E1 / 2) measured was exactly the same as in Application Example 1 described above.
It was 0.25 μJ / cm ² .

<Effect of the Invention> According to the method of the present invention, the Bragg angle (2θ ± 0.2 degrees) 27.
Oxyphthalocyanine crystals having three major diffraction peaks can be obtained in an industrially advantageous manner, for example, by obtaining a single-stage treatment with good yield.

Further, the electrophotographic photoreceptor using the oxytitanium phthalocyanine crystal thus obtained as a charge generation material has high sensitivity, low residual potential, high chargeability, and small variation due to repetition. Since the influence of the charging stability is good, it can be used as a highly durable photoconductor. Also, since the sensitivity is high in the range of 750 to 800 nm, it is particularly suitable for a photoreceptor for a semiconductor laser printer.

[Brief description of the drawings]

1 and 4 show X-ray diffraction spectra of the crystalline oxytitanium phthalocyanine of the present invention obtained in Examples 1 and 2. 2 and 3 show X-ray diffraction spectra of known α-type and β-type oxytitanium phthalocyanines, respectively.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masako Takeuchi 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Research Institute (56) References JP-A-2-215866 (JP, A)

Claims (1)

(57) [Claims] 1. An oxytitanium phthalocyanine in an aliphatic carboxylic acid solvent in sulfuric acid or R.SO ₃ H (wherein R represents an aliphatic or aromatic residue which may have a substituent). Heat-treated with a sulfonate represented by the formula X
Angle in X-ray diffraction spectrum (2θ ± 0.2 °) 2
A method for producing an oxytitanium phthalocyanine crystal, which comprises obtaining a crystal having a main diffraction peak at 7.3 °.